1. Field of the Invention
The present invention relates to a method of forming three dimensional, prefabricated concrete modules, and to a form assembly for forming the vertical walls thereof.
2. Description of Related Art
At one time, many months and a large labor force were necessary in order to construct an office or apartment building. Workers would typically first erect a large steel frame, and then pour concrete slabs and walls directly on the structure. This traditional approach was labor intensive, time consuming and expensive.
Several approaches were subsequently developed to construct office and apartment buildings at a lower cost and in a shorter period of time than the traditional method. For example, U.S. Pat. No. 3,812,637 (Yang et al.) teaches a method for erecting a reinforced concrete building in which concrete floor slabs, wall panels and box units are prefabricated at a factory and transported to the building site. The various components are arranged at the building site by crane, and laborers connect the components together to form a building. Unfortunately, a building constructed with this method has a large number of joints, which serve to weaken the building in an earthquake or under severe wind loading. Furthermore, extensive labor time is required to interconnect the many prefabricated components.
U.S. Pat. No. 4,525,975 (McWethy) discloses a method for erecting a building in which modules having a concrete base and lightweight side walls are stacked aside and upon one another to form a building. Concrete is poured between the spaced walls of the modules to form supporting concrete walls. One advantage of this approach is that the modules may be constructed at the building site. However, the need to pour a large number of concrete walls within the building causes delays, as the concrete walls must dry at each floor before the next floor can be added. Additionally, substantial labor is required to pour the concrete walls.
Other methods have been developed in which modules are fabricated on the ground and then lifted into place on the building. However, these methods require substantial manual labor for such tasks as opening and closing the concrete forms, locking and unlocking the forms, and/or installing blockouts for doors and windows before the concrete is poured. Consequently, the module fabrication process is time consuming and labor intensive.
Existing methods generally also do not provide convenient access to the vertical rebar structure, which is typically constructed within vertical wall forms. As a result, it is very difficult to readjust the location of electrical conduits, connector boxes and other vertical wall components that move out of position before the concrete is poured.